Big consumers of power such as factories and companies can select and purchase natural energy today. An example of a service that allows a consumer of power to specify and purchase natural energy is a service that provides new power as described in Non Patent Literature 1 “Tradable Green Certificates” (Japan Natural Energy Company Limited, http://www.natural-e.co.jp/green/, 2014, Dec. 3).
Electricity that is generated by natural energy (renewable energy) such as wind power, solar light and biomass (biological resources) is called “green electricity”, and it has “environmental value” that contributes to CO2 emission reduction and has a low impact on the environment, in addition to “value as electricity”. “Tradable green certificates” are certificates that certify “environmental value”, thus separating “environmental value” from “value as electricity”. A consumer of power who specifies and purchases natural energy can receive tradable green certificates in accordance with the performance of power consumption.